ML20100Q300
| ML20100Q300 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 03/04/1996 |
| From: | Benes G COMMONWEALTH EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9603110568 | |
| Download: ML20100Q300 (14) | |
Text
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Commonweahh litiwn Company 1.aSalle Generating Station a
2601 North 2 bt Road 4
Marseilles, 11.613614757 Tel Et,5357-6 61 March 4,1996 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555 l
Subject:
LaSalle County Nuclear Power Station Units 1 and 2 i
Comed Response to Revise the Exemption Request Regarding the Main Steamline Isolation Valve (MSIV) Leakage Control i
System (LCS) Alternate Leakage Treatment (ALT) Path Submittal NRC Docket Nos. 50-373 and 50-374 i
References:
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(a)
G. Benes letter to U. S. NRC, dated August 28,1995, LaSalle Submittal Regarding Elimination of the Main Steamline Isolation Valve (MSIV)
Leakage Control System (LCS) Alternate Leakage Treatment (ALT) j Path.
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(b)
P. L. Piet letter to U. S. NRC, dated November 14,1995, Request for Amendment to Facility Operating Licenses NPF-11 and NPF-18, Appendix A, Technical Specification; Incorporation of Option B, Appendix 4
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The purpose of this letter is to revise the Appendix J exemption request which j
was included with the Reference (a) submittal. On July 26,1995, the Nuclear Energy Institute issued NEI 94-01, Industry Guideline for Implementing j
Performance-Based Option of 10 CFR Part 50, Appendix J. On August 28,1995 Comed submitted Reference (a), the Technical Specification amendment request to delete the MSIV Leakage Control System and increase the allowed main steam line leakage through the isolation valves. The Reference (a) submittal also included an exemption request, included as Attachment C, from 10 CFR 50 Appendix J, which is now Appendix J Option A. On October 26,1995, the new performance based Containment Leakage Testing Rule,10 CFR 50, Appendix J, Option B became effective. On November 14,1995, LaSalle submitted a request for Technical Specification amendment (Reference (b)) to implement the new performance based Containment Leakage Testing Rule,10 CFR 50, Appendix J, Option B.
The Reference (b) submittal is currently being reviewed by the NRC.
Therefore, due to the difference between the wording of Options A and B, the exemption request requires revision. Option B separates local leak rate tests, Type B and C, from the acceptance criteria for a Type A test, as explained in section 9.2.6 of the aforementioned NEI 94-01 guidance. Therefore, no Type A k:\\nla\\tasalla\\meMee6.wpf 9603110568 960304 PDR ADOCK 05000373 4
I A Unicom CompJn)
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USNRC (2)
March 4,1996 test exemption regarding MSIV leakage is required. Due to an oversight, the Reference (a) submittal requested this Type A test exemption. Cost savings and dose savings that are expected, based on deletion of the MSIV Leakage Control System and increasing the allowed main steam line leakage through the isolation valves, have been added. Also, information on the original exemption from 100FR50, Appendix J is added, demonstrating that this exemption is a revision to the original exemption rather than a new exemption. Other wording changes have been made to clarify the exemption request.
An exemption requires a License Amendment, but no Significant Hazards Consideration other than that associated with the Technical Specification change.
l Therefore, no safety evaluation in accordance with 10 CFR 50.59 is required. The original Significant Hazards Consideration included with the Reference (a) submittal is still valid. This revised request will replace the original Attachment C, included with Reference (a), in its entirety.
1 If there are any further questions, please contact this office.
Sincerely, GBw Gary G. Benes Nuclear Licensing Administrator Attachment cc:
H. J. Miller, Regional Administrator - RIII M. D. Lynch, Project Manager - NRR P. G. Brochman, Senior Resident Inspector - LaSalle Office of Nuclear Facility Safety - IDNS k:\\ala\\lasalle\\malvies6.wyf
e e
ATTACHMENT C APPiJCATION FOR EYEMPTION TO APPENDIX J OF 10CFR50 l
i Pursuant to Section 50.12(a) of the Regulations of the Nuclear Regulatory Cammission, Comed, holder of Facility Operating Licenses NPF 11 and NPF-18, I hereby requests a revision to previously granted exemption to Appendix J of 10 CPR Part 50 " Primary bactor Containment Leakage Testing for Water-Cooled Power Reactors".
l Specifically, Comed requests a revision to the exemption granted (References 1 l and 2) conceming conducting MSIV leakage test at a reduced pressure and l exclusion of the leakage rate for main steam lines through the main steam l isolation valves (MSIVs) in the combined local leak rate test (Type B and C), as defined in the regulations of 10CFR50, Appendix J, (now Option A), Paragraphs III.C.2 and III.C.S.
l The purpose of limiting the combined local leak rate test (Type B and C) leakage is to ensure that the measured leak rate from the containment volume will not l
exceed the designed containment leak rate assumed in the safety analysis for a postulated design basis Loss of-Coolant Accident (LOCA).
In conjunction with this application for exemption request, Comed is transmitting an application for a license amendment pursuant to 100FR50.90. This license amendment involves a proposed change to the Technical Specifications, as given in l Attachment B of Reference 4, to permit an increase in the allowable leak rate for the MSIVs from the current 100 scfh through all four main steam lines to 100 scfh per steam line (400 scfh for all four main steam lines), and to eliminate the l requirements for the MSIV Leakage Control System. The safety analysis has been revised to assess the radiological effects of MSIV leakage following a postulated l design basis LOCA (Attachment G of Reference 4) being controlled using the l MSIV Leakage Alternate Leakage Path. Comed has demonstrated that the proposed change does not involve a significant hazards consideration (Attachment l D of Reference 4).
This proposed exemption is a result of the extensive work performed by the BWR Owners' Group (BWROG) in support of the resolution of Generic Issue C-8 "MSIV Leakage and LCS Failure".
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1 I 10 CFR 50, Appendix J, (currently Option A) Paragraph III.C.2 requires local leak l rate tests to be performed at accident pressure and III.C.3 for including the MSIV 1
l leakage in the summation for the local leak rate tests. LaSalle County Station
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l currently has an exemption concerning the leakage testing of the MSIVs as I approved by section 6.2.6.1 of &ference 1 as follows:
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"'Ibe design of the main steam isolation valves is such that testing in the j
l reverse direction tends to unseat the valve. Testing of the two valves j
l simultaneously, between the valves, at design pressure would lift the disc at l
the inboard valve. This would result in a meaningless test. The proposed i
l test calls for a test pressure of 20.2 pounds per square inch gage to avoid I
lifting the disc at the inboard valve. The total observed leakage through j
l both valves (inboard and outboard) is then conservatively assigned to the i
l penetration. We conclude that this procedure is acceptable. Furthermore, i
l excluding the leakage from the summation for the local leak rate tests is l
acceptable since the leaksge has been accounted for separately in the j
l radiological analysis of the site.
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l "We conclude that leak testing the main steam isolation valves in the I
manner described above is an acceptable alternative to the requirements of I
Appendix J."
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l The radiological analysis referred to in the current exemption was evaluated and I accepted in section 15.3.2.2 of &ference 1 for 11.5 scfh per line and as accounted
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l for separately from the DBA accident leakage of I. The radiological analysis was g
I based on the design of the MSIV I2akage Control System assuring that any MSIV i
l leakage would be collected and discharged ultimately through the Standby Gas I Treatment system beginning 20 minutes after the DBA LOCA release to the I environment begins. This was reevaluated and accepted in section 15.3.2.2 of i
l &ference 2 for 25 scfh per line. The leakage through the MSIVs was based on a I revised radiological analysis based on the MSIV 12akage Control System and the j
l result of the increased leakage total calculated dose consequences being less than
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I the acceptance criteria of section 15.4.9, Appendix D of the Standard hview Plan.
l As a result, the basis of the exemption in 6.2.6.2 of &ference 1 was not changed j
l and the increased allowed leakage was approved for Unit 1 in amendment 18 to j
l Operating License NPF-11 and the Unit 2 initial Operating License NPF 18.
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l The issuance of Unit 1 and Unit 2 Technical Specifications set the test pressure i
l above 20.2 psig, at a new value of 25 psig, which is not requested to be changed.
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l The dele'tlon of the MSIV Leakage Control System changes the release path that I was assumed for the original exemption and associated radiological analysis.
j l %erefon, a revision to the current exemption is requested, based on the I acceptability of the proposed release path and the new radiological analysis.
l l Refemace 3 bas requested an amendment to the LaSalle County Station Unit 1 I and 2 Technical Specifications to support implementation of 10 CFR 50, Appendix l J, Option B - Performance Based Requirements. Option B, Paragraph III.B l includes the following requirement:
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"%e tests must demonstrate that the sum of the leakage rates at accident 1
l pressure of Type B tests, and pathway leakage rates from Type C test, is i
l less than the performance criterion (La) with margin, as specified in the l
Technical Specification."
l l L, is defined in Option B Paragraph II as the maximum allowable leakage rate at as specified in Technical Specifications. P is defined in Paragraph II pressure P, lated peak containment internal pressure r, elated to the design l
as the calcu l
l loss-of coolant accident as specified in Tachnical Specifications. As a result of l implementation of the Technical Specification. amendment to implement Option B l of 10 CFR 50 Appendix J, the following exemption is requested:
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I 1.
%e reduced pressure test exemption basis (described in Reference 1) is not I
changed, but the paragraph referenced in 10 CFR 50 is changed to 10 CFR l
50, Appendix J, Option B, Paragraph III.B. from 10 CFR 50, Appendix J, i
Paragraph III.C.2.
l l 2.
%e increased MSIV leakage and the revised leakage path based on the l
associated dose consequences requires a revision to the current exemption 3
l from the sum of leakage rates of Type B and C tests required by 10 CFR 50, l
Appendix J, Option B, Paragraph III.B.
The following discussion provides a detailed justification and evaluation of the proposed exemption. The proposed exemption is found to be authorized by law, will not present an undue risk to the public health and safety, and is consistent with the common defense and security. Furthermore, special circumstances are l present that warrant the granting of this revised exemption.
The proposed exemption will not cause additional operational activities that may significantly affect the environment. It does not result in a significant increase in any adverse environmental impact previously evaluated in the Final Environmental Impact Statement-Operating License Stage, result in a significant C-3 a
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change in effluents or power levals, or affect any matter not previously reviewed i
by the Nuclear Regulatory Commission that may have a significant adverse environmental impact.
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l %erefore, pursuant to 10CFR50.12(a), Comed hereby requests the revised j
l exemption for LaSalle Station Units 1 and 2 for excluding leakage thavugh the l main steam lines of 100 acfh through any one line, with a limit of 400 acfh l through all 4 lines and conducting the test at a reduced pressure of 20.2 psig, from l the requirements specifiM in Appendix J Option B of 100FR50. %is will revise an exemption granted by NUREG 0519 as modified by NUREG 0519, Supplement 6 (References 1 and 2).
A.
Justification i 10CFR50, Appendix J, Option B, Paragraph III.P. of the regulation requires that the combined leakage rate for all penetrations. and isolation valves, as measured during local leak rate tests (Type B and Type C), is less than the performance criterion (La) with margin, as specified in the Technical Specification.
The limitations on primary containment leakage rates ensure that the total containment leakage volume will not exceed the value assumed in the accident analyses at the peak accident pressure. As an added conservatism, the measured l leak rate is further limited to provide margin to the maximum allowable leak rate during the performance of the periodic tests to account for possible degradation of the containment leakage barrier between leakage tests.
The maximum containment leakage rate was included in the radiological analysis l of a postulated design basis LOCA as evaluated in Section 15.6.5 of the Updated l Final Safety Analysis Report (UFSAR). The radiological analysis calculated the effect of the maximum leakage rate from the containment volume in terms of control room and off-site doses, which were evaluated against the dose guidelines of 100FR50, Appendix A (General Design Criteria 19) and 100FR100, respectively.
Leakages from the containment volume were contaiwi in the reactor building (secondary containment), filtered by the Standby Gas Treatment System, and released to the environment through the elevated release stack. %e maximum containment leakage rate includes leakages through structures, all penetrations identified as Type B, and all containment isolation valves identified as Type C.
! The safety analysis has been revised to account for the radiological effects from l increased MSIV leakage in addition to those of other containment leakages following a postulated design basis LOCA. Unlike the treatment path for other containment leakages, the treatment of MSIV leakages employs the main steam i
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I dram pipmg (Alternate Leakage Paths A and B, ALT paths A and B) and the condenser. Fission products are removed by plate-out and hold up in the I relatively large volume of the main steam piping and condenser.
i The treatment method for MSIV leakages is recommended by the BWROG in i
support of the resolution to Generic Issue C-8. The Sargent & Lundy walkdowns i
l (Attachments H and I of Reference 4) as supported by additional information I provided to the NRC in References 5 through 9 have also determined that the new
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l ALT leakage pathway meets the seismic performance criteria for an SSE I earthquake. In addition, the BWROG has evaluated the availability of main I steam system piping, ALT paths A and B, and the condenser for processing MSIV I leakage, and has determined that the probability of a near coincident LOCA and a l
l seismic event is much smaller than for other plant safety risks.
l The leakage from the MSIVs should not be included in the combined local leak j
l rate test (Type B and Type C) acceptance criteria per current exemption and the
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l revised exemption, because a specific allowable leak rate has been allocated for the MSIVs in Surveillance Requirement 4.6.3.6.a of the Technical Specifications.
2 The deletion of the LCS is proposed partly in response to the safety concern I identified by Generic Issue C-8 that the MSIV Leakage Control System would not I function at high MSIV leakage rates since the process capability of the MSIV l Leakage Control System at LaSaile is designed for MSIV leakage rates of no more l than 100 scfh. If leak rates did exceed 100 scfh, the MSIV Leakage Control Sysem I will shut down, which could result in radiological release limits outside of the DBA l LOCA analysis.
As discussed earlier, the basis for the containment leakage tests and the acceptance criteria is to ensure that the measured leak rate will not exceed the maximum leak rate assumed in the safety analysis. The safety analysis for a i design basis LOCA has been revised to include the maximum MSIV leak rate, which is separate from the maximum containment leak rate. MSIV leakages will be verifie i as part of the local leak rate test. This test ensures that the measured MSIV leak rate will not exceed the allowable leak rate assumed in the safety analysis.
l Considering the doses calculated in Attachment G of Reference 4, there is sufficient micgin to the applicable limits to allow for possible degradation of the MSIV leakage barrier between leakage tests. Thus, a safety margin exists.
Furthermore, Comed will institute into the MSIV maintenance and test program, the nquirement that any MSIV exceeding the proposed limit will be repaired and i
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re tested to meet a leakage rate of less than or equal to 25 scfh. This will assure continuation of high quality repair and refurbishment efforts to improve the i
overall performance and reliability of the MSIVs.
Therefore, the proposed exemption from the acceptance criteria of 10CFR50, I
l Appendix J will not defeat the underlying purpose of the regulation, and is consistent with the safety analysis.
B.
Authorized By Law The proposed exemption is consistent with Section 3.6.1.2 of the Standard l Technical Specification (NUREG 0123). The reason for this exemption is explained in section A above. A review of the Technical Specifications for BWRs l indicates that the following plants have similar exemption from including MSIV I leakage in the total of Type B and C leakage, with a leakage tes' at reduced l pressure: Fermi 2, Hatch 1 & 2, Hope Creek,, Limerick 1, Shoreham, LaSalle 1
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and 2, Hanford, Clinton, Grand Gulf 1, Perry, Dresden 2 and 3, Monticello, Quad Cities 1 and 2, Brunswick 1 and 2 and Nine Mile Point 2.
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l The following plants have been granted similar exemptions from 10 CFR 50 4
l Appendix J concerning the deletion of the MSIV Leakage Control System and the l increased allowable main steam line leakage through isolation valves:
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Plant Hatch, Unit 2, Georgia Power Company, letter dated June 20,1995 I
l l 2.
Susquehanna Steam Electric Station, Units 1 and 2, Pennsylvania Power I
and Light Company, letter dated August 15,1995 (TAC NOs. M91013 and l
M91014).
Therefore, the proposed exemption is authorized by law.
C.
No Undue Risk to Public Health and Safety l
The proposed exemption presents no undue risk to public health and safety. The revised MSIV leakage rate has been incorporated in the radiological analysis for a postulated LOCA as an addition to the designed containment leak rate. The analysis demonstrates an acceptable increase to the dose exposures previously calculated for the control room and off site. The revised LOCA doses remain well within the guidelines of 10CFR100 for off site doses and 10CFR50, Appendix A, I
I (General Design Criteria 19) for the control room doses. In addition, the proposed I changes to Surveillance Requirement 4.6.3.6.a of the Technical Specifications have l provided for allowable main steam line leak rates through the isolation valves, C-6
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i i which ' assure that the main steam line isolation function is not compromised.
l Main steam line leakage through the isolation valves is subjected to plate-out, and hold up in the main steam piping and condenser, thus minimizing their effect on I
the total dose released.
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l Also, the existing MSIV Leakage Control System is not reliable and contains many I instruments and equipment which are subject to failures. In addition, the MSIV l Leakage Control System will not function properly if a leakage rate higher than I 100 scfh occurs as a result of excessive MSIV leakage. As a result of the possible j
l failure and limited capacity of the MSIV Leakage Control System, release limits I could possibly be exceeded during and after a DBA LOCA.
As discussed in Section F of this attachment, the proposed change will not I adversely affect the conclusions of the previously issued Final Environmental l Statement (NUREG 0486), dated November 1978. Therefore, the proposed i revision to this exemption presents no undue risk to public health and safety.
D.
Consistent with Common Defense and Security l With regard to the " common defense and security" standard, the granting of the requested exemption is consistent with the common defense and security of the United States. The Commission's Statement of Considerations in support of the exemption rule note with approval the explanation of this standard as set forth in Long Island Lightine Compan_y (Shoreham Nuclear Power Station, Unit 1), LBP-84-45,20 NRC 1343,1400 (October 29,1984). There, the term " common defense and security" refers principally to the safeguarding of special nuclear material, the absence of foreign control over the applicant, the protection of Restricted Data, and the availability of special nuclear material for defense needs. The granting of the requested exemption will not affect any of these matters and, thus, such grants are consistent with the common defense and security.
E.
Special Circumstances Are Present Special circumstances are present which warrant issuance of this requested exemption. These special circumstances are discussed in accordance with the classification contained in 100FR50.12(aX2):
(ii)
Application of the regulation in the particular circumstances would not serve the underlying purpose of the rule or is not necessary to achieve the underlying purpose of the rule.
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The underlying purpose of the rule is to limit releases to within the off site and control room dose guidelines of 10CFR100 and 10CFR50, Appendix A (GDC 19),
I respectively. Compliance with Appendix J of 10CFR50 for inclusion of main steam l line leakage through the MSIVs as part of the sum of the Type B and C leak rate l test results and conducting the test at containment design pressure is not l necessary to achieve the underlying purpose of the rule. This is true, because l main steam line leakage through the MSIVs is accounted for in separate dose I calculations in addition to the reactor primary containment DBA I.OCA dose
. The MSIV's leakage is directed through main steam piping based on L, at PALT paths into the condenser. Compliance with 100FR50, l
using one of two l
l Appendix J, Option B, paragraph III.B for inclusion of main steam line leakage I through the MSIVs in the sum of the Type B and C leak rate test results is not I necessary, since a specific leak rate limit for main steam line leakage through the l MSIVs is already specified in Surveillance Requirement 4.6.3.6.a of the Technical l Specifications. The test method involving a reduced pressure test is not changed l from the original exemption granted in Reference 1.
l The radiological consequences of MSIV leakage following a design basis LOCA I have been reanalyzed. The analysis has demonstrated that the revised II)CA doses are well within the off-site and control room dose guidelines of 10CFR100 and GDC 19.
(iii)
Compliance would result in undue hardship or other costs that are significantly in excess of those contemplated when the regulation was adopted, or that are significantly in excess of those incurred by others similarly situated.
J l Compliance with 10 CFR 50, Appendix J, Option B, paragraph III.B for inclusion l of main steam line leakage through the MSIVs in the sum of the Type B and C l leak rate tests, results in undue hardship or other costs that are significantly in excess of those contemplated when the regulation was adopted. The proposed increase in the MSIV allowable leak rate will not be possible if the leak rate I results of main steam line leakage through the MSIVs are included in the sum of l the Type B and C leak rate tests.
I Compliance requires unnecessary repair and re testing of the MSIVs and leak test I boundary valves. For example, in the Unit I sixth refuel outage, the A main I steam line inboard MSIV, and in the Unit 2 sixth refuel outage, the B main steam i line inboard MSIV, each required corrective maintenance to reduce leakage.
l These two repairs required a total of 1591 man hours and resulted in a dose c?
l 10.8 rem. The estimated maintenance costa per year for the two Units associated I with the MSIVs and leakage boundary valves due to failed leak rate tests is l $60,000, with an estimated dose of 2 rem per year. The disassembly and
i-I refurbishing of MSIVs, which is required to meet the low leakage limits, I contributes to repeated failures based on industry experience as described in J Section 3 of the, "BWROG Report for Increr. sing MSIV Leakage Limits and l Elimination of Leakage Control Systems", NEDC-31858P, Revision 2, dated l September 1993.
I l Examples of these MSIV maintenance induced defects include machining induced seat cracking, machining of guide ribs, excessive pilot valve seat machining, and mechanical defects induced by assembly and disassembly. By not having to i
disassemble the valves and refurbish them for minor leakage, LaSalle avoids introducing w: cf the root causes of recurring leakage. Industrial experience suggests that, by attempting to correct minimal defects in the valves, it is likely that some actual defects may be introduced that lead to later leak test failures.
l Also, the MSIV Leakage Control System maintenance and surveillance l requirements during both r.o: mal plant operation and during plant outages I require significant cost and dose. The work on the MSIV Leakage Control System I involves monthly functional tests and refuel cycle calibrations on 23 instruments l per unit costing $200,000 per year for the two Units. 16 MSIV I4akags Control l System motor operated valves per Unit require surveillances and diagnostic l testing in accordance with Generic Letter 89-10, costing $85,000 per year for the l two Units. The instrumentation and operating surveillances alone account for an
[ additional 2 rem per year of radiation exposure.
l l The total annual savings for eliminating the MSIV Leakage Control System and I increasing the leakage through the main steam lines for the 2 units is $345,000.
I Also, the elimination of the MSIV Leakage Contrcl System in conjunction with l higher allowed leak rates, reduces outage length by an estimated 3 days.
l In addition, the frequent maintenance work and the MSIV Leakage Control l System surveillance requirements result in needless dose exposure to maintenance l personnel of an estimated 4 Rem per year for the two Units, leading to additional economical burdens, and are inconsistent with As Low As Reasonably Achievable (ALARA) principles.
(iv)
The exemption would result in benefit to the public health and safety that compensates for any decrease in safety that may result from the i
grant of the exemption.
Comed has transmitted to the NRC an application for a license amendment which involves proposed changes to the Technical Specifications to increase the allowable 4
I MSIVs leak rate from 100 scfh through all four main steam lines to 100 scfh per steam line (400 scfh for all four main steam lines), and to delete the requirements C9
i I for the MSIV Leakage Control system. For the MSIV leak rate limit, this application is partly based on the fact that the current limit is too restrictive and results in excessive MSIV maintenance and repair, leading to additional MSIV failures, which in turn result in higher leakage. The proposed limit will benefit the public health and safety by reducing the potential forMSIV failures, and thus keeping the MSIV leakage within the radiological analysis values, i For the MSIV Leakage Control System, the proposed changes involve a I replacement of the existing MSIV Leakage Control System with the more reliable I and effective main steam piping AIII' leakage path to the condenser method for MSIV leakage treatment. The effectiveness of the proposed method, even for leakage rates greater than the proposed increased allowable limits, ensures off site dose limits to the public are not exceeded. Overall, the p% treatment d
method can handle MSIV leakage over an expanded operating range, and will l thereby resolve the potential safety concern that the ILS will not function at MSIV leakage rates higher than the LCS capacity. Thus, a margin of safety exista. Furthermore, it is clearly a safety improvement to mplace a system with I known limitations with the ALT leakage path to the condenser, which has more l than adequate capacity to limit dose to the public due to MSIV leakage.
l The exemption from 10 CFR 50, Appendix J, Option B, paragraph III.B for I excluding the main steam line leakage through the MSIVs from the sum of the l Type B and C leak rate tests is required so that LaSalle can operate with the proposed Technical Specification value of 100 scfh per steam line (400 scfh for all l four main steam lines). The above benefits will compensate for any decrease in safety that may result from the granting of the exemption.
l Thus, special circumstances exist warranting the granting of the exemption.
F.
EnvironmentalImpact Assessment l The proposed action is to revise the current exemption from 10 CFR 50, Appendix l J, Option A Paragraphs III.C.2, which exempts LaSalle County Station Units 1 l and 2 from the requirement to perform MSIV leak rate testing at the calculated I peak containment pressure related to the design basis accident, and III.C.3, which l requires that the MSIV measured leak rates be included in the combined local l leak rate test results. Comed is proposing to re-apply for the exemption based on l a proposed change to the current exemption description; specifically, the j elimination of the MSIV leakage Control System, use of the alternate leakage l treatment method, and increasing the assumed MSIV leakage rate from 25 scfh, l not to exceed 100 scfh for all four main steam lines to 100 scfh per steam line, not l to exceed a total of 400 scfh for all four main steam lines. 'Ihe proposed C-10 l
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i' l exemption will maintain the leak rate testing of the MSIVs at a reduced pressure j
l (i.e.,20.2 peig when applied between valves) and will continue to exclude the i
l measured leakage from the combined local leak rate test results.
l %e Need for the Pronaamd Action l
l l %e original exemption of 100FR50, Appendix J,Section III.C.2, which mquins l leak rate tMag isolation valves at the peak calculated conteinment pmssure l related to the design basis accident, was requested, sinos the design of the MSIVs l is such that testing in the reverse direction tends to unaast the valve, resulting in I a meaningless test. However, the exemption needs to be revised to reference l 10CFR50, Appendix J, Option B, Paragraph III.B. %e results of a test at P l would not serve the underlying purpose of the rule. The curant LaSalle Co,unty l Station Unita 1 and 2 MSIV leak rate test method is adequate, and maintaining I this method (i.e.,20.2 psig when applied between valves) will ensure the msults of I future MSIV tests will be evaluated on a similar basis. %e total observed leakage I
l resulting from a leakage test where two MSIVs on one steam line are tested l
l simultaneously, between the valves, utilizing a reduced test pressure will continue l
l to be conservatively assigned to the penetration.
1 l
l l The original exemption of 10 CFR 50, Appendix J,Section III.C.3, which requires l
l that the measured MSIV leak rates be included in the combined local leak rate l test results, was requested and is proposed to be revised. The exemption needs to l be revised to reference 10CFR50, Appendix J, Option B, Paragraph III.B. %is I leakage rate will continue to be accounted for separately in the radiological site I analysis, and therefore, the exemption meets the underlying purpose of the rule.
l l Environmental Imnacts of the Proposed Action l
I The existing exemption is proposed to be retained, and is justified, since the l proposed changes would not result in a significant increase to the LOCA doses l previously evaluated against the off site and Main Control Room dose limits I contained in 10 CFR 100 and 10 CFR 50, Appendix A, General Design Criteria 19, I respectively. As described in the preceding Section A, Justification, the method of l calculating the revised doses is conservative, and the doses resulting from a i postulated design basis LOCA are below regulatory limita.
l l Alternative to the Procosed Action l
l Since we have concluded that there is no significant environmental impact l associated with the requested exemption, any alternativec would have either no or l greater environmental impact.
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l The principal alternative would be to deny the requested exemption which would I require the performance of a 10 CFR 50, Appendix J, MSIV leak rate test at peak l calculated containment pressure and as described in the preceding "Need For 'Ibe l Proposed Action," the results of such a test on the 14Salle County Station Units 1 l and 2 design, would not serve in underlying purpose of the rule. Since the MSIV 1 test leakage rate is accounted for separately in the radiological site analysis, the l exemption meets the underlying purpose of the rule and no other alternative is l necessary. In addition, this exemption is included as part of Standard Technical l Specifications (NUREG 0123) and is consistent with regulatory practices.
l l Alternative Use of Resources l
l This proposed exemption does not involve the use of any resources not previously l considered in connection with the Nuclear Regulatory Commission's Final l Environmental Statement (NUREG 0486), dated November 1978, related to the l operation of the LaSalle County Station Units 1 and 2.
l l Information Suonorting a Finding of No Significant Imnact l
l Comed has concluded, based on the preceding environmental assessment, that the l proposed action will not have a significant effect on the quality of the human l environment; therefore, an environmental impact statement for the requested l exemption would not be required.
I G.
References:
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1.
Safety Evaluation Report Related to the Operation of Lasalle County l
Station Units 1 and 2, Docket Nos. 50 373 and 50-374, NUREG-0519, I
dated March 1981.
l l
2.
Safety Evaluation Report Related to the Operation of Lasalle County l
Station Units 1 and 2, Docket Nos. 50-373 and 50 374, NUREG-0519, l
Supplement No. 6, dated November 1983.
l l
3.
P. L. Piet letter to U. S. NRC, dated November 14,1995, Request for l
Amendment to Facility Operating Licenses NPF-11 and NPF 18, l
Appendix A, Technical Specification; Incorporation of Option B, 1
Appendix J.
I C-12
.r l
G. Benes letter to U. S. NRC, dated August 28,1995, LaSalle l
Submittal Regarding Elimination of the Main Steamline Isolation l
Valve (MSIV) Leakage Control System (LCS) Alternate Leakage l
Treatment (ALT) Path.
l l
5.
G. Benes letter to U. S. NRC, dated December 15,1995, Response to l
questions from the NRC Staff transmitted in the NRC RAI dated l
November 16,1995.
l l
6.
G. Benes letter to U. S. NRC, dated February 5,1996, Response to l
questions from the NRC Sta# transmitted in the NRC RAI dated l
February 1,1996.
l l
7.
G. Benes letter to U. S. NRC, dated February 9,1996, Supplemental l
information to the LaSalle Submittal dated August 28,1995.
l l
8.
February 20,1996 telephone conference between Comed and NRR l
involving LaSalle Station's MSIV LOS ALT Path.
l l
9.
G. Benes letter to U. S. NRC, dated February 28,1996, Supplemental l
l information to the LaSalle Submittal dated August 28,1995.
C-13
.